The monsoon season in India brings relief from the summer heat but also comes with its own set of health challenges. Along with common illnesses like dengue, malaria, and diarrhoea, there’s another disease that people often overlook: leptospirosis.

Leptospirosis is caused by a bacteria found in floodwater that is contaminated with animal urine. Urban hubs like Mumbai, with its annual bouts of severe flooding, are particularly susceptible to leptospirosis outbreaks.

While often overlooked, it’s crucial to be aware of this disease, particularly during the monsoon months. This year, Mumbai has already seen about 141 cases of leptospirosis in the month of July as per the data revealed by BMC.

Extreme waterlogging in Mumbai where recently 141 cases of Leptospirosis have been reported. Exposure to flooded water is one of the root causes of leptospirosis. (Source: Govandi Citizen Welfare Forum.)

According to WHO, Leptospirosis was first identified by Adolf Weil in 1886. Weil’s disease, a severe form of leptospirosis named after its discoverer, was traditionally linked to rat-borne infections caused by the bacteria Leptospira icterohaemorrhagiae and Leptospira copenhageni.

In the early 20th century, researchers in Japan and Germany discovered that the bacteria causing leptospirosis were actually the same ones Weil had described. Since then, scientists have recognized that all types of leptospiral infections should be called leptospirosis, regardless of their symptoms.

In India most cases of leptospirosis were reported from the coastal belt which includes Gujarat, Tamil Nadu, Maharashtra, Kerala, Karnataka, Andaman and Nicobar Islands, reveals a study conducted by National Library of Medicine.

Health on Air interviewed Dr. Karthik Sunki, MBBS, MD, DVL, for an in-depth look at leptospirosis. The following is an edited transcript of the interview.

How does the transmission of this disease happen?

The most common method of transmission is through direct contact with infected urine or other bodily fluids such as saliva, or contaminated water, soil, or food. This bacteria can enter the body through skin or mucous membranes (eyes, nose, mouth) especially if skin is broken with cut or scratch. Outbreaks are most commonly associated with contaminated water such as flood waters.

What are the symptoms?

Clinical presentation of leptospirosis is variable depending on the stage of the disease. Time between a person’s exposure to the source and the appearance of symptoms varies from two days to 4 weeks. Early state signs and symptoms include high fever, headache, chills, muscle aches, vomiting, jaundice, red eyes, abdominal pain, diarrhea, and rash.

The second stage presents with more severe symptoms such as kidney or liver failure, meningitis, haemorrhage, hepatomegaly, pulmonary haemorrhage, and ARDS.

How severe can it get?

Without treatment, Leptospirosis can lead to serious problems such as: kidney damage, meningitis, liver failure, respiratory distress, or even death. Case fatality is 1-5%.

Does it affect both humans and animals?

Animals usually are not affected but they act as carriers of the bacteria and act as reservoirs. And in humans it causes infection.

How can infrastructural gaps contribute to this disease, especially during monsoons when many areas develop water logging? How dangerous it gets for people during this time to catch leptospirosis?

Monsoons, floods and water logging increases the risk of leptospirosis as there is more chances of contamination from the infected animals. People living in urban slums with inadequate sanitation and poor housing are at high risk of rat exposure and leptospirosis.

People aren’t very aware of leptospirosis, what is the first signal to consult a doctor and what action should be taken for awareness?

If a person develops fever after exposure to flood water they can consult a doctor. Extensive public outreach campaigns should be conducted to spread awareness about leptospirosis. To prevent the spread of the disease, it is recommended to implement measures such as rat eradication programs, better sanitation practices in agricultural areas, regular cleaning of cattle sheds, vaccination of cattle, routine medical check-ups for both animals and humans.

How should one take care of themselves during this time? 

• After flooding, make water safe to drink by boiling it or using a chemical treatment.
• Cover cuts or scratches with waterproof bandages or other coverings that seal out water.
• Avoid contact with floodwater or any fresh water source that might contain animal urine.
• Wear waterproof protective clothing and footwear when in areas with potential animal urine contamination, such as floodwaters or contaminated soil.
• Prevent rodent infestations by storing food, water, and garbage in sealed containers and using traps.